When we design information technology we risk building specific metaphors and models of human activities into the technology itself and into the embodied activities, work practices, organisational cultures and social identities of those who use it. This paper is motivated by the recognition that the assumptions about human activity used to guide the design of particular technology are made active, in use, by the interaction design of that technology. A fragment of shared design work is used to ground an exploration of different solutions to one of the technical problems that arise when technology is used to support similar work over distance. The argument is made that some solutions to design problems are better than others because they enable human interaction in different ways. Some solutions enhance the possibilities for human agency, others diminish it. This means that there can be a moral basis for choosing between alternative interaction design decisions that might otherwise be considered equivalent in terms of the functionality and usability of the technology.